Survival of Lawsonia intracellularis in porcine peripheral blood monocyte-derived macrophages

Carlos Eduardo Real Pereira, Talita Pilar Resende, Aníbal G. Armién, Ricardo Pereira Laub, Fabio Augusto Vannucci, Renato Lima Santos, Connie Jane Gebhart, Roberto Mauricio Carvalho Guedes

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Lawsonia intracellularis, an obligately intracellular enteric bacterium, infects intestinal epithelial cells, but may also be found within macrophages in the intestinal lamina propria of affected pigs. Macrophages play an important role in host defense against infectious agents, but the role of this cell in L. intracellularis infection is not well understood. The aim of this study was to evaluate the permissibility of macrophages to L. intracellularis infection in vitro. Pure culture of L. intracellularis was added to swine peripheral blood monocyte-derived macrophages. Viability of intracytoplasmic L. intracellularis was evaluated at different time points by transmission electron microscopy (TEM). Potential replication of L. intracellularis in macrophages was also evaluated by qPCR. By TEM, phagocytosis L. intracellularis within of phagolysosomes were observed 1-hour post-infection (hpi) and bacterial structures in binary fission at 48 hpi. The number of intracellular bacteria was determined at 1, 4, 24, 48, and 72 hpi by qPCR in infected macrophages and compared to the number of intracellular bacteria from culture in McCoy cells. In both cell lines, the amount of L. intracellularis was decreased at 4 hpiand increased at 24 hpi. The number of intracellular bacteria continued to increase in McCoy cells over time. This is the first study showing interaction, survival and propagation of L. intracellularis in macrophages. These findings are critical to establish an experimental model for future studies of the pathogenesis of porcine proliferative enteropathy and the potential persistence of L. intracellularis in macrophages during chronic infections.

Original languageEnglish (US)
Article numbere0236887
JournalPloS one
Volume15
Issue number7
DOIs
StatePublished - Jul 2020

Bibliographical note

Publisher Copyright:
Copyright: © This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.

Keywords

  • Animals
  • Cell Line
  • Desulfovibrionaceae Infections/veterinary
  • Intestinal Diseases/microbiology
  • Lawsonia Bacteria/growth & development
  • Macrophages/microbiology
  • Phagocytosis
  • Swine
  • Swine Diseases/microbiology

PubMed: MeSH publication types

  • Research Support, Non-U.S. Gov't
  • Journal Article

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